Robust site-resolved quantum gates in an optical lattice via inhomogeneous control

Ultracold atoms in optical lattices are an important platform for quantum information science, lending itself naturally to quantum simulation of many-body physics and providing a possible path towards a scalable quantum computer. To realize its full potential, atoms at individual lattice sites must be accessible to quantum control and measurement. This challenge has so far been met with a combination of high-resolution microscopes and resonance addressing that have enabled both site-resolved imaging and spin-flips. Here we show that methods borrowed from the field of inhomogeneous control can greatly increase the performance of resonance addressing in optical lattices, allowing us to target arbitrary single-qubit gates on desired sites, with minimal crosstalk to neighboring sites and greatly improved robustness against uncertainty in the lattice position. We further demonstrate the simultaneous implementation of different gates at adjacent sites with a single global control waveform. Coherence is verified through two-pulse Ramsey interrogation, and randomized benchmarking is used to measure an average gate fidelity of ~95%. Our control-based approach to reduce crosstalk and increase robustness is broadly applicable in optical lattices irrespective of geometry, and may be useful also on other platforms for quantum information processing, such as ion traps and nitrogen-vacancy centers in diamond.Comment: Originally submitted version. Longer version with some substantive edits to appear in Nature Communication

Three-dimensional light-matter interface for collective spin squeezing in atomic ensembles

We study the three-dimensional nature of the quantum interface between an ensemble of cold, trapped atomic spins and a paraxial laser beam, coupled through a dispersive interaction. To achieve strong entanglement between the collective atomic spin and the photons, one must match the spatial mode of the collective radiation of the ensemble with the mode of the laser beam while minimizing the effects of decoherence due to optical pumping. For ensembles coupling to a probe field that varies over the extent of the cloud, the set of atoms that indistinguishably radiates into a desired mode of the field defines an inhomogeneous spin wave. Strong coupling of a spin wave to the probe mode is not characterized by a single parameter, the optical density, but by a collection of different effective atom numbers that characterize the coherence and decoherence of the system. To model the dynamics of the system, we develop a full stochastic master equation, including coherent collective scattering into paraxial modes, decoherence by local inhomogeneous diffuse scattering, and backaction due to continuous measurement of the light entangled with the spin waves. This formalism is used to study the squeezing of a spin wave via continuous quantum nondemolition (QND) measurement. We find that the greatest squeezing occurs in parameter regimes where spatial inhomogeneities are significant, far from the limit in which the interface is well approximated by a one-dimensional, homogeneous model.Comment: 24 pages, 7 figure

Accurate Microwave Control and Real-Time Diagnostics of Neutral Atom Qubits

We demonstrate accurate single-qubit control in an ensemble of atomic qubits trapped in an optical lattice. The qubits are driven with microwave radiation, and their dynamics tracked by optical probe polarimetry. Real-time diagnostics is crucial to minimize systematic errors and optimize the performance of single-qubit gates, leading to fidelities of 0.99 for single-qubit pi rotations. We show that increased robustness to large, deliberately introduced errors can be achieved through the use of composite rotations. However, during normal operation the combination of very small intrinsic errors and additional decoherence during the longer pulse sequences precludes any significant performance gain in our current experiment.Comment: 9 pages, 7 figure

NPP VIIRS Early On-Orbit Geometric Performance

The NASA/NOAA Visible Infrared Imager Radiometer Suite (VIIRS) instrument on-board the Suomi National Polar-orbiting Partnership (NPP) satellite was launched in October, 2011. The instrument geometric performance includes sensor spatial response, band-to-band co-registration (BBR), and geolocation accuracy and precision. The geometric performance is an important aspect of sensor data record (SDR) calibration and validation. In this paper we will discuss geometric performance parameter characterization using the first seven-month of VIIRS' earth and lunar data, and compare with the at-launch performance using ground testing data and analysis of numerical modeling results as the first step in on-orbit geometric calibration and validation

Impact of Satellite Geometric Distortions on Landscape Analysis: Effects on Albedo

Data from wide field-of-view sensors have been providing information about the Earth's surface since the early 1980's. This manuscript is the result of investigations designed to determine the effective resolution and geometric variability of the NASA Earth Observing System MODerate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imager Radiometer Suite (VIIRS) gridded data. Although the wide field-of-view and high temporal frequency of MODIS provide near-daily global coverage, inconsistent observation assignment in geolocated MODIS pixels measurably demonstrates how spatial accuracy is affected by pixel-size growth (up to 4.8x) along-scan. For studying the effective resolution, the point spread function of nominal 250m MODIS gridded surface reflectance products (L2G) was estimated from [man-made] large size targets. The findings indicate that in near-optimal locations the resolution of (sinusoidal grid) gridded products varies between 344m-835m along-scan for a range of viewing angles, but also indicate location-dependent variability with along-scan and along-track ranges of 314m-1363m and 284m-501m respectively. Albedo was identified as a well-known physical metric to study the effects of geometric variability, thus a broadband albedo using MODIS-like geometry was simulated for five EOS validation sites. Results of each site simulation exhibit compounded uncertainty attributable to the geometric distortion in ranges sufficient to influence climate models (i.e. ranges from 0.01-0.045 albedo). A second series of broadband albedo simulations was developed for the same five EOS validation sites using VIIRS-like geometries and aggregation zones. Spatially heterogeneous land cover demonstrated a marginally significant difference in the mean albedo between aggregation zones (< 0.015). Results from data simulating temporal compositing, demonstrate the influence of geometric artifacts through differing levels of uncertainty between periods (i.e. ranges from 0.01-0.05 albedo). The variability in both MODIS and VIIRS L2G questions the standard application of a global fixed grid, and indicates that regional projections combined with a representative grid cell 4x the nominal detector size (i.e. 1000m and 1500m for MODIS and VIIRS, respectively) are potentially useful for products using off-nadir views. This work ultimately resolves the surface-feature representation of temporo-spatial wide field-of-view instrument observations and quantifies the results of associating inherently-variable observations into an artificially-fixed and geometrically-regular space

Gestión administrativa y el uso de las TIC’s en una entidad educativa de Lima, 2021

Ante todo, la investigación se titula: Gestión administrativa y el uso de las TIC's en una entidad educativa de Lima, 2021, tuvo el propósito de determinar la relación existente entre la variable Gestión administrativa y la variable Uso de las TIC's. La investigación se realizado bajo un diseño correlacional no experimental, ya que se utilizo la recolección de información en función a las variables ya mencionadas, se aplico la técnica de la encuesta y el instrumento utilizado fue el cuestionario, que fue validado por tres expertos, para la confiabilidad de este ultimo se utilizo el Alfa de Cronbach dio como resultado 0,939 para la variable Gestión administrativa y 0.884 para la variable Uso de las TIC's. Debido a la cantidad de personas se optó por considerar como muestra a toda la población que fueron 70 personas entre personal docente y administrativo. Los resultados obtenidos de la investigación nos indican la existencia de una correlación positiva moderada entre las variables Gestión administrativa y Uso de las TIC's , ya que el Rho de Spearman resulto 0.501, de igual modo se identificó una correlación positiva moderada entre la dimensión planeación y la variable Uso de las TIC's, ya que el Rho de Spearman resulto 0.504, se identificó una correlación postiva moderada entre la dimensión organización y la variable Uso de las TIC's, ya que el Rho de Spearman resulto 0.432, se identificó una correlación positiva moderada entre la dimensión dirección y la variable Uso de las TIC's, ya que el Rho de Spearman resulto 0.514 y finalmente se identificó una correlación positiva baja entre la dimensión control y la variable Uso de las TIC's, ya que el Rho de Spearman resulto 0.38